Better handling of binary data.  Possibilities:
  o Buffer command to hold the data
  o vprintf style command for parsing the data.
Better C langauge API
Change dp_RPC semantics to correctly handled multiple RPC's on
  the same socket.
     Case 1) A RPC B; B RPC A; A RPC B
     Case 2) A RPC B; B RDO A; A RPC B
  In case 1, the order of replies on the socekt is fixed (a stack will
  work).  In case 2, the order is unpredictable.  So we need sequence
  numbers on the RPCs.
